diff --git a/app/src/main/java/net/micode/notes/data/Contact.java b/app/src/main/java/net/micode/notes/data/Contact.java
index d97ac5d..d376b43 100644
--- a/app/src/main/java/net/micode/notes/data/Contact.java
+++ b/app/src/main/java/net/micode/notes/data/Contact.java
@@ -26,48 +26,52 @@ import android.util.Log;
 import java.util.HashMap;
 
 public class Contact {
-    private static HashMap<String, String> sContactCache;
-    private static final String TAG = "Contact";
+    private static HashMap<String, String> sContactCache;//定义hashmap sContactCache，联系人缓存
+    private static final String TAG = "Contact";//不能更改TAG
 
     private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
     + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
     + " AND " + Data.RAW_CONTACT_ID + " IN "
             + "(SELECT raw_contact_id "
             + " FROM phone_lookup"
-            + " WHERE min_match = '+')";
+            + " WHERE min_match = '+')";//选择呼叫者呼叫的ID，当其等于该号码时获取
 
     public static String getContact(Context context, String phoneNumber) {
         if(sContactCache == null) {
             sContactCache = new HashMap<String, String>();
-        }
+        }//为联系人缓存分配空间，如果它没被分配
 
         if(sContactCache.containsKey(phoneNumber)) {
             return sContactCache.get(phoneNumber);
-        }
+        }//返回电话号码
 
         String selection = CALLER_ID_SELECTION.replace("+",
                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        //使呼叫者id的替换方法赋予选择
         Cursor cursor = context.getContentResolver().query(
                 Data.CONTENT_URI,
                 new String [] { Phone.DISPLAY_NAME },
                 selection,
                 new String[] { phoneNumber },
-                null);
+                null);//cursor指向context的query方法返回值
 
         if (cursor != null && cursor.moveToFirst()) {
             try {
                 String name = cursor.getString(0);
                 sContactCache.put(phoneNumber, name);
                 return name;
-            } catch (IndexOutOfBoundsException e) {
+            }//返回名字
+            catch (IndexOutOfBoundsException e) {
                 Log.e(TAG, " Cursor get string error " + e.toString());
                 return null;
-            } finally {
+            } //处理异常
+            finally {
                 cursor.close();
-            }
-        } else {
+            }//释放
+        } //令cursor返回到第一条
+        else {
             Log.d(TAG, "No contact matched with number:" + phoneNumber);
             return null;
-        }
+        }//号码不匹配
     }
 }